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Many objects studied in astronomy follow a power law distribution function, for example the masses of stars or star clusters. A still used method by which such data is analysed is to generate a histogram and fit a straight line to it. The…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 Thomas Maschberger , Pavel Kroupa

It is important to correctly subtract point sources from radio-interferometric data in order to measure the power spectrum of diffuse radiation like the Galactic synchrotron or the Epoch of Reionization 21-cm signal. It is computationally…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-29 Samir Choudhuri , Somnath Bharadwaj , Nirupam Roy , Abhik Ghosh , Sk. Saiyad Ali

Radio interferometry is a powerful technique that allows astronomers to create high-resolution images of astronomical objects. The distribution of radio telescopes in an interferometer is a critical factor that determines the resolution and…

Instrumentation and Methods for Astrophysics · Physics 2024-09-04 Elio Quiroga Rodriguez

Visibility-visibility correlation has been proposed as a technique for the estimation of power spectrum, and used extensively for small field of view observations, where the effect of $w-term$ is usually ignored. We consider power spectrum…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 Prasun Dutta , Tapomoy Guha Sarkar , S. Pratik Khastgir

Radio interferometers, such as the Low-Frequency Array and the future Square Kilometre Array, are attempting to measure the spherically averaged 21-cm power spectrum from the Epoch of Reionization. Understanding of the dominant physical…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-01 Ivelin Georgiev , Garrelt Mellema , Sambit K. Giri , Rajesh Mondal

We derive and implement a full Bayesian large scale structure inference method aiming at precision recovery of the cosmological power spectrum from galaxy redshift surveys. Our approach improves over previous Bayesian methods by performing…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Jens Jasche , Benjamin D. Wandelt

We present an evaluative study of some current methods utilized in the analysis of infrared (IR) observatinons of star-forming regions. A series of self-consistent radiative transfer models are constructed, with the outputs analysed using…

Astrophysics · Physics 2007-05-23 S. D. Doty , M. L. Palotti

Calibration is an essential step in radio interferometric data processing that corrects the data for systematic errors and in addition, subtracts bright foreground interference to reveal weak signals hidden in the residual. These weak and…

Instrumentation and Methods for Astrophysics · Physics 2019-05-08 Sarod Yatawatta

Distributed estimation based on measurements from multiple wireless sensors is investigated. It is assumed that a group of sensors observe the same quantity in independent additive observation noises with possibly different variances. The…

Information Theory · Computer Science 2009-11-13 Shuguang Cui , Jinjun Xiao , Andrea Goldsmith , Zhi-Quan Luo , H. Vincent Poor

Many important techniques for investigating the properties of extragalactic radio sources, such as spectral-index and rotation-measure mapping, involve the comparison of images at two or more frequencies. In the case of radio…

Astrophysics · Physics 2009-11-13 S. M. Croke , D. C. Gabuzda

We study the sensitivities of space infrared interferometers. We formulate the signal-to-noise ratios of infrared images obtained by aperture synthesis in the presence of source shot noise, background shot noise and detector read noise. We…

Astrophysics · Physics 2009-10-31 Tadashi Nakajima , Hideo Matsuhara

Forthcoming high-resolution observations of the Cosmic Microwave Background (CMB) radiation will generate datasets many orders of magnitude larger than have been obtained to date. The size and complexity of such datasets presents a very…

Astrophysics · Physics 2016-08-25 Julian Borrill

Refraction by the atmosphere causes the positions of sources to depend on the airmass through which an observation was taken. This shift is dependent on the underlying spectral energy of the source and the filter or bandpass through which…

Instrumentation and Methods for Astrophysics · Physics 2019-05-01 Matthias Lee , Tamas Budavari , Ian Sullivan , Andrew Connolly

We describe an attempt to reconstruct the initial conditions for the formation of cosmological large-scale structure. The power spectrum of the primordial fluctuations is affected by bias, nonlinear evolution and redshift-space distortions,…

Astrophysics · Physics 2015-06-24 J. A. Peacock , S. J. Dodds

A variational Bayesian inference for measured wave intensity, such as X-ray intensity, is proposed in this paper. The data is popular to obtain information about unobservable features of an object, such as a material sample and the…

Machine Learning · Computer Science 2024-11-12 Akinori Asahara , Yoshihiro Osakabe , Yamamoto Mitsuya , Hidekazu Morita

Reconstruction of the linear power spectrum from observational data provides a way to compare cosmological models to a large amount of data, as Peacock & Dodds (1994, 1996) have shown. By applying the appropriate corrections to the…

Astrophysics · Physics 2009-10-30 Clay Smith , Anatoly Klypin , Michael Gross , Joel Primack , Jon Holtzman

Spatial phase-referencing in dual-field optical interferometry is reconsidered. Our analysis is based on the 2-sample variance of the differential phase between target and reference star. We show that averaging over time of the atmospheric…

Astrophysics · Physics 2009-11-07 Gerard Daigne , Jean-Francois Lestrade

New far-infrared and submillimeter data are used to solidify and to extend to long wavelengths the empirical calibration of the infrared spectral energy distribution (SED) of normal star-forming galaxies. As was found by Dale et al. (2001),…

Astrophysics · Physics 2008-11-26 Daniel A. Dale , George Helou

The coherent image distortions induced by weak gravitational lensing can be used to measure the power spectrum of density inhomogeneities in the universe. We present our on-going effort to detect this effect with the FIRST radio survey,…

The GREAT observations need frequency-selective calibration across the passband for the residual atmospheric opacity at flight altitude. At these altitudes the atmospheric opacity has both narrow and broad spectral features. To determine…

Instrumentation and Methods for Astrophysics · Physics 2012-03-09 Xin Guan , Jürgen Stutzki , Urs U. Graf , Rolf Güsten , Yoko Okada , Miguel Angel Requena Torres , Robert Simon , Helmut Wiesemeyer
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